1. Field of the Invention
The present invention relates to a coolant supply apparatus for a grinding machine for supplying coolant toward a grinding surface of a grinding wheel.
2. Discussion of the Related Art
There has been well known an automatic balancing device for automatically correcting the rotational imbalance of a grinding wheel which is attached to a wheel spindle rotatably carried on a wheel head to be rotated at a high speed. For example, in an automatic balancing device disclosed in a Japanese unexamined published patent application No. 2003-103459, two annular rotors each having an offset load portion at a part thereof are built in a rotary section secured to a wheel spindle, while two stators facing respectively with the two rotors are provided at a stationary section secured to a wheel head. As the two stators are electrified in dependence on the magnitude of an imbalance of the grinding wheel measured by a vibration gauge during a high speed rotation of the grinding wheel, the two rotors are rotated respective correction amounts, whereby the automatic imbalance correction for the grinding wheel can be performed. In this way, the imbalance of the grinding wheel is automatically eliminated, so that the imbalance of the grinding wheel can be prevented from causing chatter marks to be created on a finish surface of a workpiece which is ground with the grinding wheel.
However, it may be sometime the case that chatter marks are made on a finish surface of a workpiece even if the same is ground with a grinding wheel the imbalance of which has been corrected by the automatic balancing device. Heretofore, in order not to create the chatter marks, the imbalance of the grinding wheel has been eliminated by the balancing device each time it is detected by a vibration gauge that the imbalance of the grinding wheel exceeds a tolerance therefor. Thus, in the case that the amount of the imbalance varies, the correction for the imbalance of the grinding wheel becomes so frequent, thereby making productivity of the grinding worse.